Intrauterine contraceptive device

ABSTRACT

An intrauterine contraceptive device comprises an outer ring formed with a central membrane to prevent tissue obtrusion and control the deflection characteristics of the device, and lateral spurs slanted in a retrograde direction to impede expulsion through the cervical os. The device is molded of a plastic material and may be coated with a metal film as a barrier against calcium deposits and provide radio-opacity.

United States Patent 1 3,633,574

[72] Inventor Irwin S. Lerner 3,537,445 11/1970 Burnhill 128/130 Greenwich, Conn. 3,256,878 6/1966 Schwartz et al.. 128/ l 30 [21] Appl. No. 775,729 2,122,579 7/1938 Meckstroth 128/130 [22] Filed Nov. 14, 1968 2,432,770 12/1947 Kurkjian 128/128 [45] Patented Jan. 11, 1972 2,875,755 3/1959 HeuboskietaL. 128/127 [73] Asaignee A. H. Robbins Company, Incorporated 3,253,590 5/1966 Birnberg et a1. I 28/1 30 Richmond, Va. 3,371,664 3/1968 Pleshette 128/127 OTHER REFERENCES 54 INTRAUTERINE CONTRACEPTIVE DEVICE Time magazine 7/31/64 30 Claims, 12 Drawing Figs. Primary Examiner Richard A. Gaudet 52 us. C1 128 130 Emmimho- Dunne Int Cl I A61fg/46 Attorney-Strauch, Nolan, Neale, Nies & Kurz so FieldofSearch .II. 128/127,

l3o;46 /3o 31; ABSTRACT: An intrauterine contraceptive device comprises 74/490 Isl/35 an outer ring formed with a central membrane to prevent tise 186, n a era s urs an o 10 0 UNITED STATES PATENTS impede expulsion through the cervical 0s. The device is 1,874,596 8/1932 Olson 151/35 mowed f a plastic material and may be coated i a metal 3,422,564 l/l969 Izum1 46/31 X film as a barrier against calcium deposits and provide radio- 3,454,004 7/1969 Leininger 128/130 opacity PATENTEU JAN] 1 I972 INVENTOR IRWIN S LERNER BY flmw ATTORNEYS.

INTRAUTERINE CONTRACEPTIVE DEVICE FIELD OF THE INVENTION THE PRIOR ART Intrauterine contraceptive devices have a very long history. In recent years, however, increased attention has been focused on such devices because of the rapid rate of population increase and the resulting recognition ofa need for better contraceptive methods. The mode of operation ofintrauterine devices has not yet been definitely ascertained, but enough data has been collected to verify their contraceptive efficacy, and to reveal some of the problems associated with such devices.

One of these problems is that the devices are often expelled through the cervical os, probably as a result of the natural muscular activity of the uterus. Preventing such expulsion is difficult, since a device may be prone to this difficulty as a result of its being either too flexible or too inflexible.

For example some prior art devices are highly flexible, and in fact are designed to stretch out into an elongated linear configuration for greater ease of insertion. After insertion, these devices coil themselves into a convoluted configuration in situ. Unfortunately such devices are sometimes expelled through the cervical by the reverse process; the device is fed back out through the cervical os linearly in response to uterine contraction.

On the other hand, it is believed that some devices which respond less flexibly may be pushed out through the cervical os precisely because they fail to deform sufficiently when under compressive stress, and act as a dilating wedge.

Another problem caused by devices of too little flexibility is that they tend to generate cramps and pain to the patient because of their unwillingness to yield and deform in response to muscular activity of the uterus. As a result, the less-flexible devices require manufacture in different sizes so as to adequately fill uteri of varying sizes.

Another problem encountered with intrauterine devices has been the difficulty of fitting them to different size uteri. Usually the devices are mass produced in a single size, and must therefore be large enough to maintain appropriate contact with a large uterus, but flexible enough so that it deforms sufficiently to accommodate itself to a small uterus without undue pain or cramps.

SUMMARY AND OBJECTS OF THE INVENTION In general terms, the object of this invention is to provide an intrauterine contraceptive which is an improvement in several respects over previous devices of this kind. A more specific object is to provide an intrauterine contraceptive device which actively resists expulsion through the cervical 0s. Another specific objective is to provide a device of this kind which readily accommodates itself to a range of uterine sizes with comfort to the patient. Another such objective is to provide a device of this kind which is easier to insert. Still another objective is to provide an intrauterine contraceptive device which prevents the possibility of strangulation of a loop of bowel in an open loop of the device in the event that it protrudes or escapes into the peritoneal cavity. It is also an object of the invention to provide an intrauterine contraceptive device which may be suitably coated so as to minimize the accumulation of calcium deposits thereon.

In accordance with this invention, an intrauterine contraceptive device of the type comprising an outer ring is provided with a membrane effectively closing the control portion of the ring, and attached to a substantial length of the ring at least at opposite sides thereof. A plurality of spurs extend outwardly from the ring on opposite sides thereon, in the plane of the ring, and are slanted in a given direction so as to impede expulsion movement of the device in that direction.

An additional important aspect of this device is that it may be coated with a suitable film of material which prevents the accretion of calcium deposits upon the device after it has been in the uterus for a length of time, and enhance its effectiveness.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view ofan intrauterine contraceptive device in accordance with the present invention;

FIG. 2 is a sectional view of the ring of the intrauterine device, taken at one side thereof, along the line 22 of FIG.

FIG. 3 is a sectional view of the same ring taken at the tail end ofthe contraceptive device, along the line 33 of FIG. 1;

FIG. 4 is another sectional view of the ring taken at the head end of the device, along the line 4-4 of FIG. 1;

FIG. 5 is a longitudinal section of the tip ofa typical spur of the contraceptive device, taken along the line S5 of FIG. 1;

FIG. 6 is a transverse section ofa typical spur, taken along the line 66 of FIG. 1;

FIG. 7 is a sectional view of the intrauterine contraceptive device, taken along the line 77 of FIG. 1;

FIG. 8 is a perspective view of a modified embodiment of a contraceptive device in accordance with this invention;

FIG. 9 is a fragmentary plan view of another modification of the device;

FIG. 10 is a fragmentary plan view of yet another modification of the device;

FIG. 11 is a sectional view taken along the line 1l11 in FIG. 10; and

FIG. 12 is a plan view of still a further modification of the device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As seen in FIG. 1, the intrauterine contraceptive device 10 of this invention generally comprises an outer ring 12, a membrane l4 effectively closing the central portion of the ring, and a plurality of spurs 16-1 through 20-1 on one side of the ring and 16-2 through 20-2 on the opposite side thereof. Preferably, but not necessarily, the membrane 14 is provided with an opening 22 at the head end of the device and another opening 24 at the tail end. While it is presently preferred that membrane 14 be a continuous (albeit apertured) film of the same material as ring 12, as used herein the word membrane" is intended to include screening, grids and other perforated sheets, as well as one or more bars extending across ring 12. A small opening 26 may optionally extend transversely through the ring 12 to communicate with the membrane opening 24, provided a convenient place for securing a telltale string, which may also be used to aid in removing the device. As described and as preferred, the membrane 14 is not connected to ring 12 along its entire periphery. However, the membrane 14 may be continuously peripherally connected to ring 12 without departing from the present concepts.

In greater detail, the device 10 comprises a single piece of integrally molded plastic material which preferably has been mixed with a suitable amount of radio-opaque material to permit the device to be located by X-ray or fluoroscope techniques if necessary. A preferred plastic material is Ultrathene," a copolymer of ethylene, and a vinyl monomer material, catalogue listing UE633 of U.S. Industries, with 10 percent by weight of barium sulfate as a radio-opaque ingredient. While the proportions just mentioned are preferred, the range of barium sulfate may be anywhere from 0 to 40 percent. Alternative plastic materials which may be employed are polyethylene, polypropylene, ethylene, propylene, copolymers, and terpolymers, e.g., EPT, polyvinyl acetate, copolymers of vinyl acetate with another ethylenically unsaturated monomer copolymerizable therewith, silicone rubber, polyfluoroethylenes, e.g., Teflon, Kel-F, etc., and the like.

In accordance with one feature of this invention, the molded device 10 may be provided with a thin coating of a suitable material to inhibit the deposition of calcium upon the surface of the device after it has been in the uterus for a period of time and enhances its effectiveness. Such materials include gold, platinum, silver, copper, tantalum, and alloys of these and other metals. The coating may be vapor-deposited to a preferred thickness of approximately 5X10 inch. A preferred range of coating thickness is from 2X10 to 40X l 0 6 inch.

The outer ring 12 forms the structural framework of the device 10, and in that respect functions similarly to other ringlike structures found in some prior art devices. HOwever, the present ring 12 has a configuration which is designed, in accordance with this invention, to maximize the likelihood that the intrauterine device 10 will be retained in place after insertion in the uterus. Specifically, the ring 12 is designed to make the device flexible enough so that it yields when placed in hoop compression by the natural muscular activity of the uterus. If the device resisted such pressures unyieldingly, it might be moved in the direction of the cervical os, act as a dilating wedge, and eventually be expelled.

In addition, the ring 12 is designed to deform in a particular manner, so as to further minimize the chances of expulsion. Specifically, the cross section of the ring 12 is somewhat heavier at region 12-4 (the head end of the device 10) than it is at regions 12-2 (along the side of the device) or region 12-3 (at the tail end thereof). As seen in FIG. 4, the cross section of the ring at region 12-4 is substantially rectangular with rounded corners, and its thickness in the direction perpendicular to the plane of the ring 12 is somewhat greater than it is in the direction parallel to the plane of the ring. Preferred dimensions are a 0.07 inch perpendicular to the plane of the ring, and 0.066 inch parallel to that plane, at region 12-4.

The cross section of the ring 12 remains substantially rectangular with rounded corners throughout the length of the ring, but in the head and tail regions 12-4 and 12-3 respectively the ring thickness is greater in the direction parallel to the plane of the ring than it is in the direction perpendicular to that plane, while in the side regions 12-2 the opposite is true, i.e., the ring thickness is greater in the direction perpendicular to the plane of the ring than in the direction parallel to it. As a result, the ring 12, when subjected to hoop compression applied to the side regions 12-2 by the adjacent uterine walls, buckles first in the side regions.

One advantage of this is that the intrauterine device 10 tends to deform in response to such compression, rather than to be cammed longitudinally relative to the uterine wall. If the ring 12 buckled first at the head region 12-4, it would be subject to a camming force tending to move it toward the cervical os, with expulsion as a possible consequence. Thus the tendency of the ring 12 to buckle in the side region 12-2 helps to prevent expulsion. A second advantage resulting from such side buckling has to do with deformation of the central membrane 14, and is discussed below.

The cross section at the tail region 12-3 (see FIG. 3) has preferred thickness dimensions of 0.05 inch perpendicular to the plane of the ring by 0.06 inch parallel to that plane. Note that the cross section of the ring 12 is smaller in both directions in the tail region 12-3 than it is in the head region 12-4.

As a result, if sufficient compressive stress is exerted upon the ring 12 to buckle one of these regions, the tail region 12-3 will buckle first, thus insuring that the camming force then exerted on the device 10 will tend to move it in the direction of the head region 12-4 rather than in the direction of the tail region 12-3, since it is only the latter direction of motion which can result in expulsion through the cervical os.

The cross section at either of the side regions 12-2 (the device 10 is symmetrical about its longitudinal or head-to-tail axis) has preferred thickness dimensions of 0.066 inch perpendicular to the plane of the ring by 0.05 inch parallel to that plane. As previously mentioned, the perpendicular dimension preferably exceeds the parallel dimension in these regions, to promote buckling of the sides 12-2 in the direction parallel to the plane of the ring.

A preferred range of the various ring thicknesses mentioned extends from 0.05 inch for the smallest dimension to an upper limit of 0. I3 inch for the largest, while preserving the same relative proportions which give the device its flexibility in preferred directions to prevent expulsion. At the same time, the device 10 does not suffer from the opposite disadvantage of the long line" type ofintrauterine device which is so flexible that it can be deformed by uterine contractions into a linear shape and thus expelled through the cervical os by a reversal of the insertion process.

However, while the cross-sectional area and the dimensions of the various regions around the ring have been carefully selected so as to respond to external forces on the perimeter by deforming the entire device in a nonplanar manner, the addition of the membrane 14 produces the desired deformation regardless of the relative dimensions of height and width of the ring walls, and in fact the cross section may be rectangular or round or almost any geometric shape. When the device is subjected to external forces around its perimeter, the spurs deflect initially in response to these forces and then transmit these forces to the ring. As the ring tends to collapse, portions of the membrane respond to the compressional forces by becoming nonplanar and other portions of the membrane have a resultant force in tension causing the ring to deflect in a nonplanar manner in the region where the membrane in ten' sion is attached to the ring.

To make the above behavior more clearly obvious, consider a flat washer ofa given outside diameter and an inner concentric hole, the thickness of the washer being considerably less than the overall diameter of the washer. lf forces are applied to the perimeter of the washer it will tend to buckle nonplanarly by folding along a central axis, flat faces tending to come together. Consider now a barrel hoop with a height perpendicular to the face of the hoop) greater than the wall thickness parallel to the plane of the hoop. The response of the barrel hoop to side forces on its periphery is to fold so as to bring the inner surfaces of the hoop toward each other with the hoop remaining essentially coplanar with its original position. Now by attaching a flexible membrane approximately to the inner walls of the barrel hoop, external compression forces to the hoop will transmit tensile forces in the membrane so as to tend to make the barrel hoop distort out of its original plane.

The performance of the present device may thus be similar to the action of the barrel hoop with a membrane. Side forces on the device cause nonplanar deformation of the device and, in particular, will cause the tail region to deflect away from the exit cervical os. HOwever, to enhance the effect of nonplanar collapse, it is preferred to proportion ring 12 as above described so that the ring would collapse nonplanarly even without the presence of membrane 14.

The ring 12 also has carefully calculated overall dimensions which are designed to correspond to the midrange of normal uterine sizes, while at the same time making sufficiently firm contact with any size uterus to be firmly retained in place. Specifically, the ring 12 is of a generally elliptical configu ration in that the outside diameter of the ring along the head-totail axis is greater than the maximum outside diameter along an axis transverse thereto. The preferred outside diameter of the ring 12 along the head-to-tail or major axis is 0.775 inch, and a preferred range of outside diameters is from 0.75 to l .25 inch.

The preferred outside diameter of the ring 12 in a direction transverse to the major axis is 0.76 inch, although a preferred range of outside diameter is from 0.56 to l. 12 inch. The maximum transverse width of the ring 12 is reached at a location somewhat closer to the head end of the device, region 12-1, than to the tail end, region 12-3. This is related to the fact that the curvature of the ring 12 at the head of the device is somewhat more blunt, compared to the ring curvature at the tail end which is somewhat more pointed. The resulting trilobite, or buglike shape of the ring further increases the tendency of the device to resist being expelled tailward through the cervical os, since, apart from any considerations of buckling, an object under compression tends to be cammed toward its wider end, in this case the head region 124.

The outside diameters referred to so far in this detailed description have to do with the dimensions of the ring 12 alone. The dimensions of the entire intrauterine contraceptive device 10 are somewhat greater, taking into account the length of the spurs 16-1 through -1 and 16-2 through 20-2. In the preferred embodiment of FIG. 1, there are five such spurs on each side of the ring 12. The longest ones 16-1 and 16-2 are located nearest to the head end ofthe device, and the spurs decrease progressively in length as they approach the tail end. Moreover, the spurs preferably do not extend outwardly from the ring in a radial direction from the ring but slant toward the tail end of the device 10 so as to form an acute angle with the major axis of the ring. The value of that angle preferably decreases progressively from the foremost spurs 16-1 and 16-2 through the rearmost 20-1 and 20-2. While it is preferred that the spurs extend outwardly from ring 12 in the plane of the ring, this is not necessary and the spurs may extend away from ring 12 at angles to the plane of the ring.

The foremost spurs 16-1 and 16-2 are preferably about 0.25 inch long, measured from the outermost tip of the spur to the point at the base of the spur where its longitudinal axis intersects the extrapolated surface of the ring 12. A preferred range for this dimension is from about 0.l inch to 0.375 inch. The spurs 16-1 and 16-2 are swept back at preferred angles of about 50 to the major axis of device 10. Fillets 28 of plastic material may be provided at the roots of all the spurs to control the stiffness of the spurs.

The second spurs 17-1 and 17-2 have preferred lengths of about 0. l 8 inch, although this value may vary widely. A preferred range of length is from about 0.09 to 0.27 inch. These spurs are swept back at preferred angles of about 42 to the major axis.

The third spurs 18-1 and 18-2 have preferred lengths of about 0.148 inch. A preferred range of length is from about 0.075 to 0.3 inch, although wider variation is acceptable, and they are swept back at preferred angles of about 34 to the ma or axis.

The fourth spurs 19-1 and 19-2 have preferred lengths of about 0.135 inch. A range of about 0.065 to 0.2 inch is preferred although lengths outside of this range are useful. Spurs 19-1 and 19-2 are swept back at preferred angles of about 26 to the major axis.

The fifth and last spurs 20-1 and 20-2 have preferred lengths of only about 0.1 inch, and a preferred range of0.05 to 0.15 inch, although other lengths may be used. Spurs 20-1 and 20-2 are swept back preferably at an angle of about 20 relative to the major axis of the ring 12.

All of the dimensions above and hereafter set forth are merely preferred dimension and ranges. Wide variations in any given dimension and in relative dimensions, even beyond the limits of the preferred ranges, may be employed. Further, specifically, the relative lengths of spurs 16-1 through 20-1 and 16-2 through 20-2, while preferred as described, are not critical and spurs of higher reference character number can even be longer than those of smaller reference character number.

The preferred angular orientations given for the spurs 16-1 through 20-1 and 16-2 through 20-2 may be varied over a wide range but, preferably, they should all intersect the longitudinal axis at acute angle, and most preferably at progressively more acute angles from head to tail.

The spurs serve a number of functions. They flex closer to the ring 12 in response to the natural muscular contractions of the uterus, and thus help the overall device 10 to yield to such contractions rather than resisting and thereby increasing the chances of expulsion through the cervical 0s. The flexibility of these spurs also permits the device 10 to fit a greater range of uterine sizes, since the spurs can either remain spread out to contact a larger uterine cavity or can flex inwardly to accommodate a smaller one, while still helping to retain the device 10 in place.

Additionally, because the spurs are resilient cantilevers, they will yield to muscular contractions transverse to their length and by so yielding, apply a self-restoring force against the uterine wall to maintain the device in its position.

Most significantly, however, the spurs have a preferential direction of slant towards the tail end of the device 10 which serves to impede retrograde movement of the device 10 in the direction of the cervical 0s. The device is inserted head first; i.e., the region 12-4 enters the uterus first, followed by the tail region 12-3. As a result, reverse movement of the device 10 goes against the grain" of the spurs 16-1 through 20-1 and 16-2 through 20-2. In order to move in the reverse direction the spurs would have to be flexed outwardly from the ring 12, which is not easily accomplished. Thus by resisting such deformation the spurs impede reverse movement of the device. In contrast, upon initial insertion of the device the spurs are more easily flexed rearwardly, i.e., bent closer to the ring 12. so that they offer considerably less resistance to movement in the direction of insertion.

FIG. 5 is a longitudinal section taken through the tip of a typical one of the spurs, and shows that the tip shape is preferably substantially spherical so as to avoid injury to adjacent tissue.

FIG. 6 is a transverse section through a typical spur illustrating that the projections are preferably substantially thicker in the direction perpendicular to the plane of the ring 12 than they are in the direction parallel to the plane. The preferred dimensions are about 0.066 inch and 0.035 inch respectively, but these dimensions are not critical and could be widely varied, could be increased or decreased, keeping in mind the need for flexibility. Thus these dimensions are a function of material properties as well as other dimensions of the spurs themselves.

As a result of this preferred difference in the thickness in the two directions, the spurs flex readily toward the ring 12, while it is relatively more difficult to deflect them out of the plane of the ring 12. Thus the spurs can easily yield during initial insertion of the device 10, but it is undesirable that they be deflected too far out of the plane of the ring since that would make them less effective in impeding reverse movement of the device.

One function of the membrane 14 is to block the interior of the ring 12 so as to prevent intrusion of intestinal tissue thereinto in the event that the device 10 should be partially or completely perforated into the peritoneal cavity. The membrane 14 is attached to the inner periphery of the ring 12 over most of the length of that ring, in contrast to prior art devices lacking a central barrier or having a barrier attached only at a few points. Thus the present device is more effective in preventing the possible intrusion of intestinal tissue into the ring opening.

Moreover, the membrane 14 is thin enough to be very flexible, the preferred thickness being only about 0.006 inch and the preferred range of thickness being from about 0.002 to 0.06 inch. The result of such flexibility is that, when the ring 12 is under hoop compression by uterine muscles, the mem brane has a tendency to buckle out of the plane ofthe ring 12 and consequently to bear against the internal wall of the uterus. This additional contact against the uterine wall is a further factor in resisting expulsion of the device 10 when muscular contractions take place.

In order to enable the membrane 14 to buckle more easily in this manner, it is detached from the ring 12 preferably at two locations 30 and 32 adjacent to the head region 12-4 and tail region 12-3 respectively. Freeing the membrane 14 from the ring 12 at these locations increases the likelihood that it will buckle along a line roughly corresponding to the major axis of the device. In addition, since the ring 12 itself yields preferentially in the side regions 12-2 where the membrane 14 is primarily attached, it carries the attached edges of membrane 14 along with it. causing the membrane to deform outwardly from the plane of ring 12 to make contact with the uterine wall.

The relieving of the membrane 14 at locations 30 and 32 is preferably carried to the extent of providing the two distinct openings 22 and 24, previously mentioned as among the general features of the device 10. These openings are not essential, but opening 22 is useful for cooperation with certain types of uterine insertion devices, while opening 24 is useful for cooperation with an extracting hook. The latter can be inserted through the opening 24 at the tail end of the device 10 for withdrawing it through the cervical os.

At the tail end of the device 10 there may be provided a telltale string 50 which extends out through the cervical so that the presence of the intrauterine device can be verified by vaginal examination. The telltale string 50 may, if desired, be inserted through the opening 24 and tied around the ring 12 in the region 12-3. However, the hole 26 approximately 0.02 inch in diameter may be provided for the purpose of securing string 50. If hole 26 is provided the telltale string may be inserted through the hole 26 and thereby tied to the ring 12 as shown in FIG. 1 Another way of securing string 50 is to mold string 50 integral with the remainder of device to thereby eliminate the connection problem and the costs incurred therein, as shown in FIG. 9.

In an alternative embodiment of the invention, an intrauterine contraceptive device 100 as seen in FIG. 8 includes a ring 112, and spurs 116-1 through 120-1 and 116-2 through 120-2 which are similar to their counterparts in the device 10 discussed earlier. However, the central membrane 114 of this embodiment differs in that it is formed with accordion pleats 140 which fold upwardly out of the plane of the ring 112, and alternate accordion pleats 142 which fold downwardly out of that plane. in addition, the membrane 114 is completely separated from the ring 112 for a considerable length thereof at the head end 112-1 and the tail end 112-3. This configuration of the membrane 114 allows it to buckle out of the plane of the ring 112 and particularly easily in response to compressive forces exerted on the ring 112, and the pleats 140 and 142 provide definite fold lines along which such buckling takes place preferentially. Furthermore, the pleats 140 fold upwardly to contact one wall of the uterus, while the alternative pleats 142 simultaneously fold downwardly to engage the opposite wall. Thus the membrane 114 engages both walls of the uterus simultaneously, the better to impede reverse motion of the intrauterine contraceptive device 100. In this embodiment a telltale string 150 is shown tied around the tail section 112-3 ofthe ring 112.

Another feature of the accordion folding membrane is that the entire device can be compressed into a compact configuration with the membrane neatly folded within the configuration so as to provide no obstruction or impediment to its introduction through the cervical os into the uterus.

Referring now to FIGS. 10 and 11 a further modification of the device is shown. The main body of the device can be substantially identical to the embodiments of FIGS. 1, 8 or 9. However, a dilator in the form ofa round or oval ball 52 may be molded integrally with the ring 12 at the head end 12-4 thereof whereby to permit insertion of the device with the dilator ball or sphere 52 preceding the remainder of the device to gently spread the uterine wall during insertion whereby to prevent injury thereto.

As best shown in FIG. 12, the membrane need not be apertured as heretofore described. That is to say the membrane can enclose the entire central passage of the ring 12 as does the membrane 214 for the ring 212 for the device 210 of FIG. 12.

However, it has been found that insertion of the device is facilitated by the inclusion of one or more apertures 22 and 24. Accordingly, the embodiment of FIG. 1 is preferred.

lrrespective of the form of the membrane, be it continuous or apertured, a film or a grid, an advantage of including the membrane is that it prevents tissue growth which would entrap the device as by growing around the ring through the open center thereof if the membrane were not present. So long as apertures 22 and 24 are sized sufficiently small, they will not adversely interfere with this function of the membrane.

The skilled gynecological clinician will recognize that there are a number of suitable instruments for inserting and withdrawing any of the devices of the present invention. One suitable inserter which may be used in connection herewith is described in U.S. Pat. No. 2,176,559 and the disclosure thereof in said patent is incorporated herein by reference.

it will now be appreciated that the present invention provides an intrauterine contraceptive having significant advantages over prior art devices of this kind. The contraceptive device itself resists the deposition of calcium on the surface thereof even after it has been in the uterus for some time, fits a wide variety of uterine sizes, resists expulsion, and prevents possible intestinal strangulation by effective closure of the central opening in the event of partial or complete uterine perforation.

Since the foregoing description and drawings are merely illustrative, the scope of protection of the invention has been more broadly stated in the following claims; and these should be liberally interpreted so as to obtain the benefit of all equivalents to which the invention is fairly entitled.

The invention claimed is:

1. An intrauterine contraceptive device made from material enabling flexing to conform to the uterine cavity comprising: a central body having a perimeter portion with nose, tail and side portions and encompassing an area which can be contained within a normal uterus and at least three spaced-apart short spurs on each of said side portions extending outwardly from said perimeter portion.

2. An intrauterine contraceptive device as claimed in claim 1 wherein said spurs and said perimeter portion are disposed in substantially coplanar arrangement.

3. An intrauterine device as claimed in claim 2, wherein said spurs are made with a cross section having a first dimension in a direction transverse to the coplanar arrangement of body and spurs greater than the cross section dimension in a direction transverse to said first dimension.

4. An intrauterine contraceptive device as defined in claim 1, wherein at least some of said spurs are of varying lengths.

5. The intrauterine device as claimed in claim 1, which is molded of a plastic material, said device further comprising film means coating the surface of said plastic for preventing calcium deposits thereon.

6. The intrauterine device as claimed in claim 5, wherein said film coating is a biologically inactive metal coating.

7. An intrauterine device as claimed in claim I, wherein said central body comprises a ringlike unit with nose and tail portions and side portions joining said nose and tail portions; and said spurs include a multiplicity of short spurs integral with each side portion extending outwardly and having retrograde inclination.

8. The intrauterine device as claimed in claim 7, wherein: the ring thickness in the direction perpendicular to the plane of said ring exceeds the ring thickness in the direction parallel to said plane at said opposite sides of said ring; and the ring thickness in the direction perpendicular to said plane is less than the ring thickness in the direction parallel to said plane at opposed nose and tail regions of said ring between said opposite sides thereof, whereby said ring buckles preferentially at said sides in response to hoop compression thereof.

9. The intrauterine device as claimed in claim 8, wherein the ring thickness at said tail region is less than at said nose region whereby said device is urged forward in response to hoop compression of said ring.

10. The intrauterine device as claimed in claim 7, wherein the ring thickness is less at said opposite side portions thereof than is the ring thickness at least at said tail region between said opposite side portions.

11. The intrauterine device as claimed in claim 7, wherein said spurs are all coplanar with said ring and slant toward said tail region for impeding tailward movement of said device to prevent expulsion thereof.

12. The intrauterine device as claimed in claim 7, further comprising a film including a biologically inactive metal coating the surface of said device for preventing calcium deposits thereon.

13. An intrauterine device as claimed in claim 7, wherein at least some of said spurs have a decreased length dimension as their positions on said side portions approach closer to said tail portion.

14. An intrauterine contraceptive device made from material enabling flexing to conform to the uterine cavity comprising: a ringlike perimeter portion having a nose portion and opposite therefrom a tail portion with side portions joining said nose and tail portions; and a plurality of spurlike retaining means extending outwardly from each said side portion.

15. The intrauterine device as claimed in claim 14, further including membrane means across at least a portion of the area encompassed by the inner perimeter of said ringlike portion.

16. The intrauterine device as claimed in claim 15, wherein said membrane is detached from said ringlike portion at two opposed locations.

17. The intrauterine device as claimed in claim 16, wherein said two locations are adjacent said nose and tail portions.

18. The intrauterine device as claimed in claim 15, wherein the flexibility of said membrane substantially exceeds that of said ringlike portion, whereby said membrane buckles out of the plane of said ringlike portion in response to hoop compression of said ringlike portion.

19. The intrauterine device as claimed in claim 15, wherein said membrane has a plurality of pleats.

20. The intrauterine device as claimed in claim 14, wherein at least a part of which is a metallic element.

21. An intrauterine device as claimed in claim 14, wherein said plurality of spurlike retaining means are short spurs integral with each said side portion and extend outwardly and have retrograde inclination.

22. The intrauterine device as claimed in claim 21, wherein: the ringlike perimeter thickness in the direction perpendicular to the plane of said ringlike portion, exceeds the perimeter thickness in the direction parallel to said plane at opposite said side portions; and said perimeter's thickness in the direction perpendicular to said plane is less than said perimeter's thickness in the direction parallel to said plane at opposed head and tail regions of said ringlike portion between said opposite said side portions, whereby said ringlike portion buckles preferentially at said sides in response to hoop compression thereof.

23. The intrauterine device as claimed in claim 21, wherein the perimeter cross-sectional area is less at said opposite side portions than at said tail portion between said opposite side portions.

24. The intrauterine device as claimed in claim 21, said spurs are all coplanar with said ringlike portion.

25. An intrauterine device as claimed in claim 14, wherein said spurlike retaining means decrease in length as their positions on said side portions approach closer to said tail portion.

26. An intrauterine contraceptive device comprising: a ring; a membrane attached to said ring along opposite sides thereof and extending therebetween, and wherein: the ring thickness in the direction perpendicular to the plane of said ring exceeds the ring thickness in the direction parallel to said plane at said opposite sides of said ring; and the ring thickness in the direction perpendicular to said plane is less than the ring thickness in the direction parallel to said plane at opposed head and tail regions of said ring between said opposite sides thereof, whereby said ring buckles preferentially at said sides in response to hoop compression thereof.

27. An intrauterine contraceptive device comprising: a ring; a membrane attached to said ring along opposite sides thereof and extending therebetween, and wherein the ring thickness is less at said opposite sides thereof than at opposed head and tail regions of said ring between said opposite sides.

28. The device as in claim 26, wherein the ring thickness at said tail region is less than at said head region whereby said device is urged forward in response to hoop compression of said ring.

29. The device of claim 28, further comprising a plurality of spurs extending outwardly from said ring on opposite sides thereof.

30. The device of claim 29, wherein said spurs are all coplanar with said ring and slant toward said tail region for impeding tailward movement of said device to prevent expulsion thereof.

wherein UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,633, 574 Dated January 11, 1972 Inventor(s) Irwin S Lerner It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Name of Assignee, change "Robbins" to -Robins--.

Col. 1, line 69, change "control" to --central--. Col. 2, line 52, change "provided" to --providing--. Col. 3, line 9, change "40xl0'" to -40xl0" line 10, delete line 12, change "rin-" to -ringline 13, change "glike" to -like--; change "However" to --However--.

Col. 4, line 5]., change "However" to -j-However--.

Signed and sealed this 20th day of June 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents ORM PO-105O (10-69) USCOMM'DC 50376-1 59 Q U.$. GOVERNMENT PRINTING OFFICE: (969 0-366-33 

1. An intrauterine contraceptive device made from material enabling flexing to conform to the uterine cavity comprising: a central body having a perimeter portion with nose, tail and side portions and encompassing an area which can be contained within a normal uterus and at least three spaced-apart short spurs on each of said side portions extending outwardly from said perimeter portion.
 2. An intrauterine contraceptive device as claimed in claim 1 wherein said spurs and said perimeter portion are disposed in substantially coplanar arrangement.
 3. An intrauterine device as claimed in claim 2, wherein said spurs are made with a cross section having a first dimension in a direction transverse to the coplanar arrangement of body and spurs greater than the cross section dimension in a direction transverse to said first dimension.
 4. An intrauterine contraceptive device as defined in claim 1, wherein at least some of said spurs are of varying lengths.
 5. The intrauterine device as claimed in claim 1, which is molded of a plastic material, said device further comprising film means coating the surface of said plastic for preventing calcium deposits thereon.
 6. The intrauterine device as claimed in claim 5, wherein said film coating is a biologically inactive metal coating.
 7. An intrauterine device as claimed in claim 1, wherein said central body comprises a ringlike unit with nose and tail portions and side portions joining said nose and tail portions; and said spurs include a multiplicity of short spurs integral with each side portion extending outwardly and having retrograde inclination.
 8. The intrauterine device as claimed in claim 7, wherein: the ring thickness in the direction perpendicular to the plane of said ring exceeds the ring thickness in the direction parallel to said plane at said opposite sides of said ring; and the ring thickness in the direction perpendicular to said plane is less than the ring thickness in the direction parallel to said plane at opposed nose and tail regions of said ring between said opposite sides thereof, whereby said ring buckles preferentially at said sides in response to hoop compression thereof.
 9. The intrauterine device as claimed in claim 8, wherein the ring thickness at said tail region is less than at said nose region whereby said device is urged forward in response to hoop compression of said ring.
 10. The intrauterine device as claimed in claim 7, wherein the ring thickness is less at said opposite side portions thereof than is the ring thickness at least at said tail region between said opposite side portions.
 11. The intrauterine device as claimed in claim 7, wherein said spurs are all coplanar with said ring and slant toward said tail region for impeding tailward movement of said device to prevent expulsion thereof.
 12. The intrauterine device as claimed in claim 7, further comprising a film including a biologically inactive metal coating the surface of said device for preventing calcium deposits thereon.
 13. An intrauterine device as claimed in claim 7, wherein at least some of said spurs have a decreased length dimension as their positions on said side portions approach closer to said tail portion.
 14. An intrauterine contraceptive device made from material enabling flexing to conform to the uterine cavity comprising: a ringlike perimeter portion having a nose portion and opposite therefrom a tail portion with side portions joining said nose and tail portions; and a plurality of spurlike retaining means extending outwardly from each said side portion.
 15. The intrauterine device as claimed in claim 14, further including membrane means across at least a portion of the area encompassed by the iNner perimeter of said ringlike portion.
 16. The intrauterine device as claimed in claim 15, wherein said membrane is detached from said ringlike portion at two opposed locations.
 17. The intrauterine device as claimed in claim 16, wherein said two locations are adjacent said nose and tail portions.
 18. The intrauterine device as claimed in claim 15, wherein the flexibility of said membrane substantially exceeds that of said ringlike portion, whereby said membrane buckles out of the plane of said ringlike portion in response to hoop compression of said ringlike portion.
 19. The intrauterine device as claimed in claim 15, wherein said membrane has a plurality of pleats.
 20. The intrauterine device as claimed in claim 14, wherein at least a part of which is a metallic element.
 21. An intrauterine device as claimed in claim 14, wherein said plurality of spurlike retaining means are short spurs integral with each said side portion and extend outwardly and have retrograde inclination.
 22. The intrauterine device as claimed in claim 21, wherein: the ringlike perimeter thickness in the direction perpendicular to the plane of said ringlike portion, exceeds the perimeter thickness in the direction parallel to said plane at opposite said side portions; and said perimeter''s thickness in the direction perpendicular to said plane is less than said perimeter''s thickness in the direction parallel to said plane at opposed head and tail regions of said ringlike portion between said opposite said side portions, whereby said ringlike portion buckles preferentially at said sides in response to hoop compression thereof.
 23. The intrauterine device as claimed in claim 21, wherein the perimeter cross-sectional area is less at said opposite side portions than at said tail portion between said opposite side portions.
 24. The intrauterine device as claimed in claim 21, wherein said spurs are all coplanar with said ringlike portion.
 25. An intrauterine device as claimed in claim 14, wherein said spurlike retaining means decrease in length as their positions on said side portions approach closer to said tail portion.
 26. An intrauterine contraceptive device comprising: a ring; a membrane attached to said ring along opposite sides thereof and extending therebetween, and wherein: the ring thickness in the direction perpendicular to the plane of said ring exceeds the ring thickness in the direction parallel to said plane at said opposite sides of said ring; and the ring thickness in the direction perpendicular to said plane is less than the ring thickness in the direction parallel to said plane at opposed head and tail regions of said ring between said opposite sides thereof, whereby said ring buckles preferentially at said sides in response to hoop compression thereof.
 27. An intrauterine contraceptive device comprising: a ring; a membrane attached to said ring along opposite sides thereof and extending therebetween, and wherein the ring thickness is less at said opposite sides thereof than at opposed head and tail regions of said ring between said opposite sides.
 28. The device as in claim 26, wherein the ring thickness at said tail region is less than at said head region whereby said device is urged forward in response to hoop compression of said ring.
 29. The device of claim 28, further comprising a plurality of spurs extending outwardly from said ring on opposite sides thereof.
 30. The device of claim 29, wherein said spurs are all coplanar with said ring and slant toward said tail region for impeding tailward movement of said device to prevent expulsion thereof. 